Fix @PostResult example in method-security

Replace @PreFilter with @Postfilter in example

Signed-off-by: Olivier <Kuba15@users.noreply.github.com>

docs/modules/ROOT/pages/servlet/authorization/method-security.adoc

@@ -695,7 +695,7 @@ Kotlin::
 ----
 @Component
 open class BankService {
-	@PreFilter("filterObject.owner == authentication.name")
+	@PostFilter("filterObject.owner == authentication.name")
 	fun readAccounts(vararg ids: String): Collection<Account> {
         // ... the return value will be filtered to only contain the accounts owned by the logged-in user
         return accounts